The present invention relates to a thin-film magnetic head for use in magnetic recording and reproducing apparatus, and more particularly to a thin-film magnetic head suitable for high-density magnetic recording.
Heretofore, thin-film magnetic heads comprise a magnetic layer deposited on a substrate by a vacuum thin-film fabrication process and patterned into a core configuration by photolithography or etching, a coil and an insulating layer deposited on the magnetic layer, and another magnetic layer deposited on the insulating layer. The magnetic layers jointly constitute a magnetic circuit of the thin-film magnetic head.
The conventional thin-film magnetic heads have surface steps or irregularities due to stepped configurations of the layers and coil. The surface steps or irregularities tend to lower the resolution with which the layers and coil are shaped by photolithography. With the low photolithographic resolution, the turns of the coil cannot be reduced in pitch unless the magnetic layers above and below the coil are increased in length. If the length of the magnetic layers are increased, however, the magnetic path is also increased and so is the magnetic reluctance of the magnetic circuit. Accordingly, the conventional thin-film magnetic heads are poor in performance.
The surface steps of irregularities also prevent the thickness of the coil from being increased. Therefore, the electric resistance of the coil is relatively large, resulting in a concomitant reduction in the magnetic pole excitation efficiency.
Because of the surface steps or irregularities, an external lead extending over the uppermost magnetic layer is bent and turned in order to be connected to coil conductors joined to the coil. Therefore, the external lead is liable to be short-circuited.